The invention concerns a method for texturing surfaces of silicon wafers comprising the steps of dipping the silicon wafers in an etching solution of water, concentrated hydrofluoric acid and concentrated nitric acid and setting a temperature for the etching solution.
A method of this kind is known from the article “Isotropic texturing of polycrystalline silicon wafers with acidic texturing solutions,” by R. Einhaus, E. Vazsonyi, J. Szlufcik et al., published in the Proceedings of the 26th PVSC, Sep. 30 to Oct. 3, 1997, Anaheim, Calif., U.S.A. In this prior method, polycrystalline silicon wafers are surface-textured in a temperature-controlled acidic etching solution comprising water, hydrofluoric acid in a concentration of 50%, and nitric acid in a concentration of 70% to reduce reflections that compromise efficiency.
Known from the documents U.S. Pat. No. 3,309,760, US 2002/0187583 A1, U.S. Pat. No. 5,681,398 and U.S. Pat. No. 5,174,855 are methods for treating surfaces of silicon wafers in order to prepare silicon for a metallization step, develop a structure, and, in the case of the last-cited documents, effect cleaning.
The object of the invention is to specify a method of the kind cited at the beginning hereof that is comparatively simple to perform, particularly on an industrial scale, and yields silicon wafers of improved efficiency.